Vacuum apparatus including a particle monitoring unit, particle monitoring method and program, and window member for use in the particle monitoring

ABSTRACT

A semiconductor manufacturing apparatus includes a processing chamber for performing a manufacturing processing on a wafer. A gas supply line for introducing a purge gas is connected to an upper portion of the processing chamber, a valve being installed on the gas supply line. A rough pumping line with a valve a is connected to a lower portion of the processing chamber. Installed on the rough pumping line are a dry pump for exhausting a gas in the processing chamber and a particle monitoring unit for monitoring particles between the valve a and the dry pump. In the semiconductor manufacturing apparatus, after the valve is opened, the purge gas is supplied to apply physical vibration due to shock wave in the processing chamber  100  so that deposits are detached therefrom to be monitored as particles.

FIELD OF THE INVENTION

The present invention relates to a vacuum apparatus including a particlemonitoring unit, a particle monitoring method and a program therefor,and a window member for use in the particle monitoring.

BACKGROUND OF THE INVENTION

A semiconductor manufacturing apparatus (FIG. 10) using plasma isemployed to perform, for example, an etching processing on asemiconductor wafer (hereinafter, referred to as “wafer”) in the courseof manufacturing semiconductor products. If particles generated during amanufacturing processing adhere to product wafers, the wafers would becontaminated, resulting in reduction in yield. Thus, a high level ofcleanness is required for the semiconductor manufacturing apparatus.

FIG. 10 illustrates a schematic configuration view of a conventionalsemiconductor manufacturing apparatus 800.

In FIG. 10, the semiconductor manufacturing apparatus 800 includes aprocessing chamber 810 formed of a cylindrical vessel for performingvarious processings on a wafer. The processing chamber 810 housestherein a wafer stage for mounting a wafer thereon, and an electrode towhich a high voltage is to be applied is buried in the wafer stage.Further, a shower head 811 a provided with a number of through holes isdisposed at an upper portion of the processing chamber 810, and theshower head 811 a serves to introduce an corrosive processing gas foruse in a manufacturing processing into the processing chamber 810 viathe through holes.

Moreover, a gas supply line formed of a tubular member is connected tothe upper portion of the processing chamber 810 to introduce a purge gasinto the processing chamber 810. A valve 811 for controlling the flowrate of the purge gas is installed on the gas supply line. Further, arough pumping line 820 formed of a thin tubular member and a main vacuumpumping line 830 formed of a thick tubular member are coupled to lowerportions of the processing chamber 810. The rough pumping line 820 andthe main vacuum pumping line 830 are merged into a gas exhaust line.

Installed on the rough pumping line 820 are a dry pump (DP) 822 forexhausting a gas from the processing chamber 810 via the gas exhaustline and a valve 821 for controlling the flow rate of the gas exhaustedby the dry pump 822.

Further, on the main vacuum pumping line 830, an automatic pressurecontroller (APC) 831, an isolation valve (ISO) 832 serving as a gatevalve and a turbo molecular pump (TMP) 833 having a gas pumping rategreater than that of the dry pump 822 are installed in that order fromthe side of the processing chamber 810.

In case of depressurizing the processing chamber 810 of thesemiconductor manufacturing apparatus 800 for the manufacturingprocessing, the processing chamber 810 is first evacuated via the roughpumping line 820 and then, after closing the valve 821, the processingchamber 810 is regulated at a desired vacuum level by means of the mainvacuum pumping line 830. When performing an etching processing duringthe manufacturing process, a high vacuum state is required, and, tomaintain the high vacuum level, the vacuum pumping via the main vacuumpumping line 830 is continued during the manufacturing process.

After the completion of the manufacturing processing, a purge gas issupplied into the processing chamber 810 via the gas supply line and isthen exhausted externally via the gas exhaust line, during whichparticles floating within the processing chamber 810 are removed fromthe processing chamber 810 along with the purge gas, so that theprocessing chamber 810 is cleaned (see, for example, Japanese PatentLaid-open Application No. H6-056999: Reference 1).

To evaluate the cleanness of the processing chamber 810, there have beenmade various attempts to monitor particles by using an optical particlemonitoring unit (PM) (not shown) which is on the market.

The particle monitoring unit is usually installed between the automaticpressure controller 831 on the main vacuum pumping line 830 and theprocessing chamber 810, between the automatic pressure controller 831and the isolation valve 832, or inside the processing chamber 810 tomonitor particles discharged from the chamber 810 in real time duringthe manufacturing processing.

As for the particle monitoring unit, its component, for example, a lensformed of glass tends to be readily corroded by a corrosive processinggas. For example, glass components of the particle monitoring unit wouldbe whitened in about a week after they are first used. Accordingly, thewhitened components need to be replaced by new ones or be subject tomaintenance work. Consequently, costs of the semiconductor manufacturingapparatus 800 are increased, while its operating time decreases. As asolution to this problem, by installing the particle monitoring unit onthe rough pumping line 820, it is possible to prevent the corrosion ofthe glass components of the particle monitoring unit.

Since it is difficult to monitor the particles that are moving at a highspeed of, for example, 20 m/sec, there has been proposed a technique forallowing the particle monitoring unit to monitor the particles bycontrolling the flow cross-sectional area of a gas that flows throughthe gas exhaust line such as the vacuum main pumping line 830 formed ofa thick tubular member, to thereby improve the probability for detectingthe particles (see, for example, Japanese Patent Laid-open ApplicationNo. H11-304688: Reference 2).

Further, the semiconductor manufacturing apparatus 800 in FIG. 10further includes a transparent window member (not shown) formed ofquartz glass (SiO₂). The window member is installed to face theprocessing chamber 810 and serves as a window for introducing, forexample, a microwave into the processing chamber 810.

If the quartz glass forming the window member is exposed tofluorine-based plasma atmosphere, the silicon (Si) atom of SiO₂ wouldreact with an active molecule such as a fluorine radical contained inthe fluorine-based plasma and then volatilize as silicon fluoride(SiF₄), thereby contaminating the wafer or depositing on the surface ofthe window member to blur it (i.e., deterioration occurs).

Typically, for the purpose of preventing such deterioration, the quartglass is heated. Further, to suppress the deterioration of the windowmember, there has been also proposed a window member formed of a membermade by dispersing a first phase of quartz into a second phase ofalumina (Al₂O₃) (see, for example, U.S. Pat. No. 6,797,110: Reference3). Furthermore, for parts such as bell jar and a focus ring which areused in the processing chamber other than the window member, there hasbeen an amorphous material of silica and alumina formed by meltingsilica (SiO₂) containing aluminum (Al) (see, for example, JapanesePatent Laid-open Application No. 2003-292337: Reference 4). All of thesetechniques aim at improving the resistance to the fluorine-based plasmaor the active molecules by forming a preset member containing aluminumtherein.

However, References 1 and 2 disclose merely the technique of monitoringparticles that are moving along with the gas exhausted from theprocessing chamber 810, but none of them discloses or suggests atechnique of monitoring deposits adhered on the inner wall of theprocessing chamber 810.

The deposits might come apart from the inner wall of the processingchamber 810 during the manufacturing process and the like, resulting ina contamination of the wafer. Therefore, it is required to evaluate thecleanness of the processing chamber 801 more precisely by monitoring thedeposits on the chamber wall as well.

In addition, when heating the quartz glass of the window member toprevent the deterioration thereof, a defect may be caused in an electriccircuit disposed within the semiconductor manufacturing apparatus 800 ordeterioration of a laser unit may be accelerated.

Furthermore, with regard to the above techniques for allowing a memberto contain aluminum therein, since aluminum atoms are dispersed insilica or quartz, the surface of the member cannot exhibit plasmaresistance or resistance to active molecules efficiently, so that thefrequency of replacing the member increases. As a result, the timerequired for the replacement work increases, which in turn results indeterioration in the productivity of the semiconductor manufacturingapparatus 800. Moreover, due to the increase of costs for thereplacements, overall costs of the semiconductor manufacturing apparatus800 rises. Further, to prevent the deterioration of the productivity ofthe semiconductor manufacturing apparatus 800 and increase of the costs,the window member for use in the particle monitoring apparatus connectedto, for example, the main vacuum pumping line also needs to meet thecondition of low frequency of replacement.

SUMMARY OF THE INVENTION

It is, therefore, a first object of the present invention to provide avacuum apparatus capable of evaluating its cleanness precisely bymonitoring particles including deposits readily detached from theapparatus, and a particle monitoring method and program employedtherein.

It is a second object of the present invention to provide a windowmember for particle monitoring which exhibits resistance to activemolecules, thus capable of reducing the frequency of its replacement.

In order to achieve the first object, there is provided a vacuumapparatus including: a vessel for defining a predetermined space; a gasexhaust unit for exhausting a gas from the vessel via a gas exhaustline; at least one gas exhaust control unit installed on the gas exhaustline, for controlling a flow rate of the gas exhausted from the vessel;a particle monitoring unit installed on the gas exhaust line betweensaid at least one gas exhaust control unit and the gas exhaust unit, formonitoring particles within the gas exhaust line; a purge unit forsupplying a purge gas into the vessel via a gas supply line; and a gassupply control unit installed on the gas supply line between the purgeunit and the vessel, for controlling a flow rate of the purge gassupplied into the vessel, wherein the gas supply control unit starts asupply of the purge gas when said at least one gas exhaust control unitpermits an exhaust of the gas, and the particles monitored by theparticle monitoring unit include the particles detached from the vesseldue to the supply of the purge gas.

With the vacuum apparatus above, since the particles detached from thevessel due to the supply of the purge gas which starts when the exhaustof the gas is permitted are monitored, it is possible to surely monitorthe particle including deposits which readily separate, enabling anaccurate evaluation of the cleanness in the vacuum apparatus.

A further apparatus includes: a processing gas supply unit for supplyinga corrosive processing gas into the vessel; and another gas exhaust unitfor exhausting the processing gas from the vessel, wherein said at leastone gas exhaust control unit prohibits the exhaust of the gas when theprocessing gas is exhausted by said another gas exhaust unit. In thisway, by prohibiting the exhaust of the gas via the exhaust line when theprocessing gas is exhausted via another exhaust line, the corrosion ofthe particle monitoring unit can be prevented and the life span thereofcan be extended.

Additionally, one of the above apparatuses is characterized in that thegas supply control unit controls the flow rate of the purge gas suchthat the pressure value of the purge gas becomes at least twice theinternal pressure of the vessel. By controlling the flow rate of thepurge gas such that the pressure value of the purge gas becomes at leasttwice the internal pressure of the vessel, shock wave can be positivelygenerated in the vessel and deposits can be surely detached therefrom.

In another aspect, one of the above apparatuses further includes a powersupply unit for generating an electric discharge within the vessel,wherein the power supply unit starts the electric discharge when said atleast one gas exhaust control unit permits the exhaust of the gas, andthe particles monitored by the particle monitoring unit include theparticles detached from the vessel due to the electric discharge. Sincethere are monitored the particles detached from the vessel due to theelectric discharge started when the exhaust of the gas is permitted inaddition to the particles detached from the vessel due to the supply ofthe purge gas, it is possible to surely monitor the particle includingdeposits which readily separate, enabling an accurate evaluation of thecleanness in the vacuum apparatus.

In order to achieve the first object, there is provided a vacuumapparatus including: a vessel for defining a predetermined space; a gasexhaust unit for exhausting a gas from the vessel via a gas exhaustline; at least one gas exhaust control unit installed on the gas exhaustline, for controlling a flow rate of the gas exhausted from the vessel;a particle monitoring unit installed on the gas exhaust line betweensaid at least one gas exhaust control unit and the gas exhaust unit, formonitoring particles within the gas exhaust line; and a power supplyunit for generating an electric discharge within the vessel, wherein thepower supply unit starts the electric discharge when said at least onegas exhaust control unit permits the exhaust of the gas, and theparticles monitored by the particle monitoring unit include theparticles detached from the vessel due to the electric discharge.

With this vacuum apparatus, since the particles detached from the vesseldue to the electric discharge which starts when the exhaust of the gasis permitted are monitored, it is possible to surely monitor theparticle including deposits which readily separate, enabling an accurateevaluation of the cleanness in the vacuum apparatus.

In a further aspect, this apparatus is characterized in that the powersupply unit generates an electromagnetic stress in the vessel due to theelectric discharge. In this way, since an electromagnetic stress isgenerated due to the electric discharge in the vessel, deposits can bepositively detached from the vessel.

In yet a further aspect, this apparatus further includes: a purge unitfor supplying a purge gas into the vessel via a gas supply line; and agas supply control unit installed on the gas supply line between thepurge unit and the vessel, for controlling a flow rate of the purge gassupplied into the vessel, wherein the gas supply control unit starts asupply of the purge gas when said at least one gas exhaust control unitpermits an exhaust of the gas, and the particles monitored by theparticle monitoring unit include the particles detached from the vesseldue to the supply of the purge gas. With this apparatus, since there aremonitored the particles detached from the vessel due to the supply ofthe purge gas in addition to the particles detached from the vessel dueto the electric discharge started when the exhaust of the gas ispermitted, it is possible to surely monitor the particle includingdeposits which readily separate, enabling an accurate evaluation of thecleanness in the vacuum apparatus.

In order to achieve the first object, there is also provided a particlemonitoring method of a vacuum apparatus having a vessel for defining apredetermined space, including the steps of: (a) exhausting a gas fromthe vessel via a gas exhaust line; (b) monitoring particles within thegas exhaust line; (c) controlling a flow rate of the gas exhausted fromthe vessel; (d) supplying a purge gas into the vessel via a gas supplyline; and (e) controlling a flow rate of the purge gas supplied into thevessel, wherein, in the step (e), a supply of the purge gas is startedwhen an exhaust of the gas is permitted in the step (c), and themonitored particles include the particles detached from the vessel dueto the supply of the purge gas.

With this particle monitoring method, since the particles detached fromthe vessel due to the supply of the purge gas which starts when theexhaust of the gas is permitted are monitored, it is possible to surelymonitor the particle including deposits which readily separate, enablingan accurate evaluation of the cleanness in the vacuum apparatus.

In one aspect, this method further includes the steps of: (f) supplyinga corrosive processing gas into the vessel; and exhausting theprocessing gas from the vessel, wherein, in the step (c), the exhaust ofthe gas is prohibited when the processing gas is exhausted in the step(g). In this way, by prohibiting the exhaust of the gas via the exhaustline when the processing gas is exhausted via another exhaust line, thecorrosion of the particle monitoring unit can be prevented and the lifespan thereof can be extended.

In another aspect, the method is characterized in that the flow rate ofthe purge gas is controlled in the step (e) such that the pressure valueof the purge gas becomes at least twice the internal pressure of thevessel. With such method, by controlling the flow rate of the purge gassuch that the pressure value of the purge gas becomes at least twice theinternal pressure of the vessel, shock wave can be positively generatedin the vessel and deposits can be surely detached therefrom.

In yet another aspect, one of the above methods further includes thestep of: (h) generating an electric discharge within the vessel, whereinthe electric discharge is started when the exhaust of the gas ispermitted in the step (c), and the monitored particles include theparticles detached from the vessel due to the electric discharge. Withthe particle monitoring method of claim 11, since there are monitoredthe particles detached from the vessel due to the electric dischargestarted when the exhaust of the gas is permitted in addition to theparticles detached from the vessel due to the supply of the purge gas,it is possible to surely monitor the particle including deposits whichreadily separate, enabling an accurate evaluation of the cleanness inthe vacuum apparatus.

In order to achieve the first object, there is further provided aparticle monitoring method of a vacuum apparatus having a vessel fordefining a predetermined space, including the steps of: (a) exhausting agas from the vessel via a gas exhaust line; (b) controlling a flow rateof the gas exhausted from the vessel; (c) monitoring particles withinthe gas exhaust line; and (d) generating an electric discharge withinthe vessel, wherein the electric discharge is started when the exhaustof the gas is permitted in the step (b), and the monitored particlesinclude the particles detached from the vessel due to the electricdischarge.

With this particle monitoring method, since the particles detached fromthe vessel due to the electric discharge which starts when the exhaustof the gas is permitted are monitored, it is possible to surely monitorthe particle including deposits which readily separate, enabling anaccurate evaluation of the cleanness in the vacuum apparatus.

This method can be characterized in that an electromagnetic stress isgenerated due to the electric discharge in the step (d). In this way,since an electromagnetic stress is generated due to the electricdischarge in the vessel, deposits can be positively detached from thevessel.

Also this method can further include: (e) supplying a purge gas into thevessel via a gas supply line; and (f) controlling a flow rate of thepurge gas supplied into the vessel, wherein, in the step (f), a supplyof the purge gas is started when an exhaust of the gas is permitted inthe step (b), and the monitored particles include the particles detachedfrom the vessel due to the supply of the purge gas. With this method,since there are monitored the particles detached from the vessel due tothe supply of the purge gas in addition to the particles detached fromthe vessel due to the electric discharge started when the exhaust of thegas is permitted, it is possible to surely monitor the particleincluding deposits which readily separate, enabling an accurateevaluation of the cleanness in the vacuum apparatus.

In order to achieve the first object, there is additionally provided aprogram for executing in a computer a particle monitoring method of avacuum apparatus having a vessel for defining a predetermined space,including: a gas exhaust module for exhausting a gas from the vessel viaa gas exhaust line; a particle monitoring module for monitoringparticles within the gas exhaust line; a gas exhaust control unit forcontrolling a flow rate of the gas exhausted from the vessel; a purgemodule for supplying a purge gas into the vessel via a gas supply line;and a gas supply control unit for controlling a flow rate of the purgegas supplied into the vessel, wherein the gas supply control modulestarts a supply of the purge gas when the gas exhaust control modulepermits an exhaust of the gas, and the particles monitored by theparticle monitoring module include the particles detached from thevessel due to the supply of the purge gas.

With this program, since the particles detached from the vessel due tothe supply of the purge gas which starts when the exhaust of the gas ispermitted are monitored, it is possible to surely monitor the particleincluding deposits which readily separate, enabling an accurateevaluation of the cleanness in the vacuum apparatus.

In order to achieve the first object, there is provided a furtherprogram for executing in a computer a particle monitoring method of avacuum apparatus having a vessel for defining a predetermined space,including: a gas exhaust module for exhausting a gas from the vessel viaa gas exhaust line; a gas exhaust control module for controlling a flowrate of the gas exhausted from the vessel; a particle monitoring modulefor monitoring particles within the gas exhaust line; and an electricdischarge module for generating an electric discharge within the vessel,wherein the electric discharge module starts the electric discharge whenthe gas exhaust control module permits the exhaust of the gas, and theparticles monitored by the particle monitoring module include theparticles detached from the vessel due to the electric discharge.

With this program, since the particles detached from the vessel due tothe supply of the purge gas which starts when the exhaust of the gas ispermitted are monitored, it is possible to surely monitor the particleincluding deposits which readily separate, enabling an accurateevaluation of the cleanness in the vacuum apparatus.

In order to achieve the second object, there is provided a window memberfor particle monitoring formed of a transparent member and installedbetween a housing for defining a predetermined space and a particlemonitoring unit for monitoring particles within the housing, wherein thetransparent member includes a transparent base; and a surface treatmentlayer formed by performing a processing on a surface of the base whichfaces a gas within the housing.

With this window member, since the transparent base member includes atransparent base and the surface treatment layer formed by performing aprocessing on a surface of the base which faces a gas within thehousing, it can efficiently exhibit resistance to active molecules,thereby reducing the frequency of replacement.

The window member can be characterized in that the surface treatmentlayer contains one material selected from a group consisting of carbon,yttrium, yttria and calcium fluoride. Since the surface treatment layercontains one material selected from a group consisting of carbon,yttrium, yttria and calcium fluoride, the window member can efficientlyexhibit resistance to the active molecules in the surface treatmentlayer, thereby positively reducing the frequency of replacement.

The carbon can be crystalline diamond or diamond-like carbon.

Further, the window member can be characterized in that the content ofthe selected material ranges from 10 to 100 mass % of the total mass ofthe surface treatment layer. Since the content of the materialconstituting the surface treatment layer ranges from 10 to 100 mass % ofthe total mass of the surface treatment layer. The resistance to theactive molecules can be enhanced.

In one aspect, the surface treatment layer contains aluminum or alumina.Since the surface treatment layer contains aluminum or alumina, it canmore efficiently exhibit the resistance to the active molecules so thatthe frequency of replacement can surely reduced.

In another aspect, the content of the aluminum or the alumina rangesfrom 10 to 100 mass % of the total mass of the surface treatment layer.Since the content of the aluminum or the alumina ranges from 10 to 100mass % of the total mass of the surface treatment layer, the windowmember can have an enhanced resistance to the active molecules.

In the window member, the processing can be a coating processing. Sincethe preset processing is a coating processing, it is possible to formthe surface treatment layer on the base with ease.

The processing can also be a doping processing. Since the presetprocessing is a doping processing, it is possible to positively form thesurface treatment layer on the base.

In some aspects, the thickness of the surface treatment layer rangesfrom 100 nm to 10 μm. Since the thickness of the surface treatment layerranges from 100 nm to 10 μm, the resistance to the active molecules canbe enhanced.

In additional aspects of the window member, the base is formed of glasscontaining silicon as a primary component, and the surface treatmentlayer is exposed to active molecules included in a gas within thehousing. In this way, since the base is formed of glass containingsilicon as a primary component, and the surface treatment layer isexposed to active molecules included in a gas within the housing, thesurface treatment layer can more efficiently exhibit the resistance tothe active molecules while preventing the silicon from being exposed tothe plasma atmosphere, thereby positively reducing the frequency ofreplacement.

In order to achieve the second object, there is further provided awindow member for particle monitoring formed of a transparent member andinstalled between a housing for defining a predetermined space and aparticle monitoring unit for monitoring particles within the housing,wherein the transparent member is formed of calcium fluoride.

With this window member, since the transparent member is formed ofcalcium fluoride, it can efficiently exhibit resistance to activemolecules, thereby reducing the frequency of replacement.

Additionally, the window member can be characterized in that the housingis formed of a vessel or a tube.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention willbecome apparent from the following description of preferred embodimentsgiven in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic configuration view of a semiconductormanufacturing apparatus including a vacuum apparatus in accordance witha first preferred embodiment of the present invention;

FIG. 2 sets forth a schematic configuration view of a particlemonitoring unit of FIG. 1;

FIG. 3 provides a graph to describe the intensity of a signal detectedby a light receiving member of the particle monitoring unit of FIG. 2;

FIG. 4 presents a timing chart for explaining the sequence of a particlemonitoring method performed by the semiconductor manufacturing apparatusof FIG. 1;

FIG. 5 depicts a graph to identify the number of particles measured bythe particle monitoring unit when performing the sequence of FIG. 4;

FIG. 6 offers a schematic configuration view of a semiconductormanufacturing apparatus including a vacuum apparatus in accordance witha third preferred embodiment of the present invention;

FIG. 7 sets forth a timing chart for explaining the sequence of aparticle monitoring method performed by a vacuum transfer apparatus ofFIG. 6;

FIG. 8 presents a detailed configuration view of a window member forparticle monitoring in accordance with a fourth preferred embodiment ofthe present invention;

FIG. 9 provides a partial cross sectional view to describe theconfiguration of the semiconductor manufacturing apparatus shown in FIG.1 in further detail; and

FIG. 10 is a schematic configuration view of a conventionalsemiconductor manufacturing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to accompanying drawings.

FIG. 1 is a schematic configuration view of a semiconductormanufacturing apparatus 1000 including a vacuum apparatus in accordancewith a first preferred embodiment of the present invention.

As shown in FIG. 1, the semiconductor manufacturing apparatus 1000 has aprocessing chamber (vacuum apparatus) 100 formed of a cylindrical vesselfor performing a manufacturing processing, such as etching, sputtering,chemical vapor deposition (CVD) or the like, on a semiconductor wafer(hereinafter, referred to as “wafer”), which serves as a substrate to beprocessed, by using plasma. The processing chamber 100 is connected to aload lock chamber having a wafer transfer arm by which the wafer isloaded into the processing chamber 100.

The processing chamber 100 includes a chamber wall 110 for defining aspace necessary for performing a manufacturing processing and a waferstage 111 installed on a bottom surface of the processing chamber 100.An electrode 113 connected to a high voltage power supply 112 is buriedin the wafer stage 111, and if a high voltage HV from the high voltagepower supply 12 is applied to the electrode 113, the electrode 113electrostatically attracts and holds (chucks) the wafer loaded on thewafer stage 111 by the transfer arm. A shower head 120 a with a numberof through holes is installed at an upper portion of the processingchamber 100 to introduce a corrosive processing gas into the processingchamber via the through holes.

Further, a gas supply line formed of a tubular member is connected tothe upper portion of the processing chamber 100 to introduce a purge gasinto the processing chamber 100. On the gas supply line, there isinstalled a valve 120 for controlling the flow rate of the purge gas tobe supplied into the processing chamber 100.

A gas of low corrosiveness, high obtainability and low price is used asthe purge gas. For example, a nitrogen gas (N₂), a helium gas (He), anargon gas (Ar), a dry air, oxygen (O₂) or the like can be employed asthe purge gas. Here, a halogen gas is not proper as a purge gas since itcorrodes glass components of a particle monitoring unit to be describedlater.

Connected to lower portions of the processing chamber 100 are a roughpumping line 200 formed of a thin tubular member with a diameter of, forexample, 25 mm and a main vacuum pumping line 300 formed of a thicktubular member with a diameter of, for example, 150 mm. The roughpumping line 200 and the vacuum pumping line 300 are merged into a gasexhaust line. The gas exhaust line exhausts gases from the rough pumpingline 200 and/or the main vacuum pumping line 300 out of thesemiconductor processing apparatus 1000.

Installed on the rough pumping line 200 are a dry pump (DP) 220 forpumping out a gas from the processing chamber 100 via the gas exhaustline; valves a an b for controlling the flow rate of the gas exhaustedby the dry pump 220, i.e., the flow rate of the gas introduced into thegas exhaust line from the processing chamber 100; and an opticalparticle monitoring unit (PM) 210 for monitoring particles between thevalves a and b.

On the main vacuum pumping line 300, an automatic pressure controller(APC) 310 for monitoring the internal pressure of the processing chamber100, an isolation valve (ISO) 320 serving as a gate valve, and a turbomolecular pump (TMP) 330 connected to the dry pump 220 are installed inthat order from the side of the processing chamber 100. The isolationvalve 320 regulates the evacuation of the processing chamber 100 by theturbo molecular pump 330. The automatic pressure controller 310 controlsthe degree of regulation by the isolation valve 320, while monitoringthe internal pressure of the processing chamber 100. The turbo molecularpump 330 has a gas pumping rate greater than that of the dry pump 220.

In the semiconductor manufacturing apparatus 1000, when depressurizingthe processing chamber 100 for a manufacturing processing, theprocessing chamber 100 is first evacuated via the rough pumping line 200until the internal pressure of the processing chamber 100 reaches apreset pressure level and then, after closing the valves a and b, theprocessing chamber 100 is evacuated to a desired pressure or vacuumlevel through the main vacuum pumping line 830, while monitoring theinternal pressure of the processing chamber 100 by mean of the automaticpressure controller 310. The vacuum pumping via the main vacuum pumpingline 300 is continued during the manufacturing processing because thecorrosive processing gas is supplied into the processing chamber 100 viathe shower head 120 a.

FIG. 2 provides a schematic configuration view of the particlemonitoring unit 210 shown in FIG. 1.

As shown in FIG. 2, the particle monitoring unit 210 includes a housing211 disposed to surround the periphery of the rough pumping line 200; alaser beam source 212 for emitting a laser beam of a wavelength in therange of, for example, a visible ray; a mirror 213 for directing thelaser beam emitted from the laser beam source 212 to the rough pumpingline 200 inside the housing 211; a beam damper 214 at which the beamarrives after passing through the rough pumping line 200; a lightreceiving member 215 for receiving laser beams scattered by particles,which flow through the rough pumping line 200, via a window member 219for particle monitoring disposed at a certain part of the rough pumpingline 200; and a lens 216 for focusing the scattered laser beams whichare incident upon the light receiving member 215. The window member 219is formed of quartz. The particle monitoring unit 210 detects the laserbeam received by the light receiving member 215 as a detection signal,as will be described later with reference to FIG. 3. As shown in FIG. 2,the light receiving member 215 is disposed at a predetermined angle withrespect to the incident direction (optical axis OP1 to be describedlater) of the laser beam. That is, an optical axis of scattered beamsOP2 lies at a preset angle with respect to the optical axis OP1.Further, the window member 219 for particle monitoring forms a part ofthe rough pumping line 200.

At least a part of the rough pumping line 200 onto which a laser beam isirradiated is made of quartz glass whose surface is partially orentirely coated with an antireflection film formed of magnesium fluoride(MgF₂), wherein the quartz glass serves as the window member 219 forparticle monitoring.

The mirror 213 is configured to perform a raster scanning of the entireregion of the inner diameter of the rough pumping line 200's crosssection within a range A around the optical axis OP1 by using the laserbeam irradiated from the laser beam source 212. Moreover, as the beamdamper 214, a black solid body having a surface with irregularities, anobject with an optical labyrinth structure and the like may be used.Further, a photomultiplier tube (PMT), a charge coupled device (CCD) orthe like can be used as the light receiving member 215.

FIG. 3 is a graph describing the intensity of a detection signaldetected by the light receiving member 215 of the particle monitoringunit 210 in FIG. 2.

As shown in FIG. 3, the signal detected by the light receiving member215 normally includes a noise signal generated due to a stray light.Since the noise signal has a predetermined noise width, a thresholdvalue of signal intensity is set in the particle monitoring unit 210 byadding a preset margin value to an upper limit of the noise width.

The particle monitoring unit 210 counts detection signals havingintensities greater than the threshold value as particles, and based onthe counted number of particles, the cleanness of the processing chamber100 can be evaluated.

FIG. 4 provides a timing chart to describe a sequence of a particlemonitoring method performed by the semiconductor manufacturing apparatus1000 in FIG. 1.

As shown in FIG. 4, when performing a particle monitoring after themanufacturing processing has been completed and the wafer has beenunloaded from the processing chamber 100, the particle monitoring unit210 is powered on and the valves a and b on the side of the processingchamber 100 are opened. At the same time, the automatic pressurecontroller 310 is turned off and the isolation valve 320 (not shown) isclosed. As a result, the evacuation of the processing chamber 100 viathe main vacuum pumping line 300 is converted into an evacuation via therough pumping line 200.

Thereafter, the valve 120 is opened, and a purge gas is supplied intothe processing chamber 100 via the gas supply line at a flow rate of,for example, 70 L/min (70000 SCCM), which is higher than that of a purgegas for a conventional purge gas cleaning. Typically, since themanufacturing processing is carried out in the processing chamber 100under the high vacuum atmosphere of, for example, 10⁻¹-10⁻⁴ Pa, thepurge gas is rapidly introduced into the processing chamber at apressure level higher than the internal pressure of the processingchamber 100, resulting in an increase in the internal pressure of theprocessing chamber 100. A pressure in the processing chamber 100 whichfinally reaches a stable value by such pressure increment is preferably133.3 Pa (1 Torr) or greater. By setting the stable pressure value to be133.3 Pa or greater, the exhaust gas from the processing chamber 100 isgiven a high viscous force, thus facilitating the discharge of particlestherewith.

Thus, the rapid inflow of the purge gas causes physical vibration of allobjects in the processing chamber 100, that is, the chamber wall 110 andthe wafer stage 111, due to a shock wave.

Further, the pressure value of the purge gas supplied into the gassupply line is preferably set to be more than twice the internalpressure of the processing chamber 100, to apply the vibration to theobjects in the processing chamber 100 securely.

Afterward, under the condition that the valve 120 is opened, a highvoltage HV is applied to the electrode 113 from the high voltage powersupply 112 three times. The application of the high voltages will bedescribed later in accordance with a second preferred embodiment of thepresent invention.

When the particle monitoring is completed, the valves 120, a and b areclosed in sequence and the isolation valve 320 is opened, to therebyreturn to the state immediately after the completion of themanufacturing processing.

Since the above-described sequence or the particle monitoring method isperformed after the manufacturing processing has been completed and thewafer has been unloaded from the processing chamber 100, contaminationof the wafer can be prevented. Moreover, it is preferred that theparticle monitoring is conducted at a time when the processing gas isnot used, to prevent the corrosion of the glass components of theparticle monitoring unit 210.

Referring to FIG. 4, when performing the particle monitoring, physicalvibration (shock wave) due to the purge gas is applied to the objectswithin the processing chamber 100.

FIG. 5 is a graph showing the number of particles measured by theparticle monitoring unit 210 through the sequence in FIG. 4. FIG. 5illustrates an example of measurement results obtained before and afterthe occurrence of vibrations due to the purge gas.

As shown in FIG. 5, a number of, for example, 9000, particles arecounted for several seconds after the valve 120 is opened. This isbecause deposits detached from the chamber wall 110, the wafer stage111, and so forth were also counted as particles. Thus, by monitoringthe particles including the deposits, the cleanness of the processingchamber 100 can be evaluated precisely. Moreover, the duration ofopening the valve 120 is set to be 1 to 5 seconds and preferably 2 to 5seconds, to obtain a time period long enough to allow the vibration todiffuse through the processing chamber 100 sufficiently.

Referring to FIGS. 4 and 5, by applying the physical vibration due tothe purge gas to the objects in the processing chamber 100 at least onetime by way of opening the valve 120, detachment of deposits isfacilitated, thus enabling accurate monitoring of particles andevaluation of the cleanness of the processing chamber 100.

Moreover, the particle monitoring is conducted after completing themanufacturing processing of the wafer. Thus, by maintaining the valve aclosed during the manufacturing processing, the inflow of the processinggas into the particle monitoring unit 210 can be prevented, so thatcorrosion of the glass components of the particle monitoring unit 210can be prevented. Consequently, the life span of the particle monitoringunit 210 can be lengthened and the productivity of the semiconductormanufacturing apparatus 1000 can be improved.

Though the first embodiment uses physical vibration generated by thesupply of the purge gas, any type of vibration other than may also beused. For example, it is also preferable to apply ultrasonic waves oftens of kHz into the processing chamber 100 in order to generatevibration. Further, in case of utilizing the physical vibration, the gassupply line is preferred to have no orifice structure at a joint whereit is connected with the processing chamber 100 or a vacuum transferchamber 100′ to be describe later.

Moreover, it is preferable to generate physical vibration plural times.In such a case, since detachment of deposits reduces every time when thegeneration of physical vibration is repeated, the number of particlesdetected tends to be reduced. Thus, it is possible to perform a nextmanufacturing processing after the cleanness of the processing chamber100 is evaluated as high.

The above first embodiment is preferably performed combined with thesecond embodiment to be described later, as shown in FIG. 4.

Since the configuration of a semiconductor manufacturing apparatushaving a vacuum apparatus in accordance with the second embodiment isidentical to that of the first embodiment, explanation thereof will beomitted; and only a distinctive feature of a particle monitoring methodof a semiconductor manufacturing apparatus 1000 will be described.

A semiconductor manufacturing apparatus 1000 in accordance with thesecond embodiment intermittently applies a high voltage HV to anelectrode 113, for example, three times from a high voltage power supply112. The applied high voltages HV are preferably not smaller than +1 kVor not greater than −1 kV. More preferably, a voltage of +1 kV and avoltage of −1 kV are applied alternately. As a result of applying thehigh voltages in this manner, an electromagnetic stress to be describedbelow can be generated efficiently.

Whenever the high voltage HV is applied, a direct current (DC) dischargeoccurs instantaneously within the processing chamber 100, whereby amomentary potential gradient is formed on the chamber wall 110 or thewafer stage 111, thus creating an electromagnetic stress. Due to thuscreated electromagnetic stress, deposits on the chamber wall 110 or thewafer stage 111 are detached therefrom, and the detached deposits aredischarged as particles along with the purge gas, to be detected by theparticle monitoring unit 210.

FIG. 5 shows the number of particles counted by the particle monitoringunit 210 when the high voltage HV is applied one time. The number ofcounted particles tends to be reduced every time the number ofintermittent application of the high voltage HV increases, fordetachment of deposits reduces with the repetition of the HVapplication. Accordingly, it is preferable to perform the application ofthe high voltage HV one to ten times and, more preferably, two to fivetimes.

In accordance with the second embodiment, detachment of deposits isfacilitated by applying a high voltage HV at least one time, so thatmore accurate particle monitoring is possible, thus enabling exactevaluation of the cleanness of the processing chamber 100.

Moreover, by repeating the intermittent application of the high voltageHV is repeated plural times, it is possible to perform a nextmanufacturing processing after the cleanness of the processing chamber100 is evaluated as high.

Furthermore, though the application of the high voltage HV is carriedout while the valve 120 is opened, as shown in FIG. 4, it is alsopossible to maintain the valve 120 closed during the HV application. Insuch a case, vibration of, for example, a wafer due to a purge gas froma gas supply line can be prevented.

In addition, though a high voltage HV is applied to form the momentarypotential gradient on the chamber wall 110 or the wafer stage 111,application of a high frequency RF (radio frequency) is also preferable.By the application of the RF, an RF discharge occurs, thereby resultingin an electromagnetic stress, as in the case of applying the highvoltage HV. In case of using the RF, the duration of the RF discharge ispreferably set to be not too long: for example, it is preferably set tobe about one second.

The second embodiment is preferably performed combined with the firstembodiment, as illustrated in FIG. 4.

In the above-described first and the second embodiment, though the gasexhaust line connected to the processing chamber 100 is configured as adual pumping system including the rough pumping line 200 and the mainvacuum pumping line 300, a triple or more pumping system is alsopreferable. Further, a case of a single exhaust line will be describedhereinbelow as a third preferred embodiment of the present invention.

FIG. 6 illustrates a schematic configuration of a semiconductormanufacturing apparatus having a vacuum apparatus in accordance with thethird preferred embodiment of the present invention.

In FIG. 6, a vacuum transfer apparatus 1000′ serving as a vacuumapparatus includes a vacuum transfer chamber 100′ provided with a singleexhaust line. The vacuum transfer chamber 100′ is employed to, forexample, a load lock chamber connected to the processing chamber 100 ofthe semiconductor manufacturing apparatus 1000 in FIG. 10, and the loadlock chamber has a transfer arm for transferring wafers. The vacuumtransfer apparatus 1000′ transfers a wafer onto the wafer stage 111 inthe processing chamber 100 by using an arm 130.

Connected to the vacuum transfer chamber 100′ is a gas supply line witha valve 120′ and a gas exhaust line 200′ with a dry pump 220′, valves a′and b′, and a particle monitoring unit 210′ installed between the valvesa′ and b′.

The configuration of the third embodiment closely resembles that of thefirst embodiment except that the main vacuum pumping line 300 isomitted. Thus, likes parts will be assigned like reference numerals, anddescription thereof will be omitted, while elaborating only distinctiveparts.

Since the turbo molecular pump 330 on the main vacuum pumping line 300is not installed in the vacuum transfer chamber 100′, the vacuumtransfer chamber 100′ is not in a high vacuum state when a particlemonitoring is performed. In such a case, a sequence as described in FIG.7 is performed after a certain vacuum level is obtained by means of thedry pump 220′. Since the sequence in FIG. 7 is identical to thatexplained in FIG. 4, description thereof will be omitted.

Referring to FIGS. 6 and 7, by applying physical vibration of due to apurge gas to objects in the vacuum transfer chamber 100′ after openingthe valve 120′, detachment of deposits can be facilitated, thus enablingaccurate particle monitoring and evaluation of the cleanness of thevacuum transfer chamber 100′.

Moreover, though the vacuum transfer chamber 1000′ has been described tohave the single exhaust line in the third embodiment, but it may havemultiple exhaust lines. In case of multiple exhaust lines, though themultiple exhaust lines have normally different conductances (theconductance represents a coefficient indicating the fluidity of a fluidsuch as a discharged gas), any exhaust line of any conductance mayemploy this embodiment.

Further, it is preferable to combine the third embodiment with thesecond embodiment. In this case, a high voltage power supply identicalto the high voltage power supply 112 is connected to the objects in thevacuum transfer chamber 100′.

In accordance with the first to the third embodiment descried above,though the cleanness of the processing chamber 100 or the vacuumtransfer chamber 100′ is inspected under the absence of a wafer therein,it is also possible to evaluate the cleanness of an object other thanthe processing chamber 100 or the vacuum transfer chamber 100′, forexample, the cleanness of a wafer therein.

For example, the cleanness of the processing chamber 100 is firstevaluated. Then, if the cleanness is found to be sufficiently high andthere is detected no more detachment of particles, a wafer is loadedinto the processing chamber 100 and the cleanness of the processingchamber 100 is evaluated again upon the presence of the wafer.Thereafter, by comparing the two evaluation results, the cleanness ofthe wafer can be determined. Likewise, by comparing evaluation resultsof two cases where a rear surface of the wafer is in contact with thewafer stage 111 and is not, the cleanness of the rear surface of thewafer can be examined.

Though a particle monitoring is performed after completing amanufacturing processing in the first to the third embodiment, it isalso possible to monitor particles prior to or during the manufacturingprocessing.

Moreover, though the gas supply line has been described to have noorifice structure at a joint where it is connected to the processingchamber 100 or the vacuum transfer chamber 100′, the gas supply linewith an orifice structure may be employed in a case where a wafer or thelike exists in the processing chamber 100 or the vacuum transfer chamber100′. Accordingly, a damage of, e.g., the wafer due to physicalvibration imposed thereon by the purge gas can be prevented.

Further, though the window member 219 for particle monitoring shown inFIG. 2 is formed of quartz in the above-described preferred embodiments,it may be formed of any material as long as it is transparent.

Moreover, the object of the present invention can also be accomplishedby providing a computer, for example, a PC 600 shown in FIG. 9 to bedescribed later with a storage medium having therein program codes(corresponding to the sequence in FIG. 4 or 7) of software for realizingthe functions of the preferred embodiments described above. In thiscase, the computer (or CPU, MPU, or the like) reads the program codesstored in the storage medium and executes them.

In addition, besides the mechanism of directly realizing the functionsof the above embodiments by executing the program codes read by thecomputer, for example, the PC 600, it is also possible to set anoperating system (OS) working on the PC 600 to perform an actualprocessing partially or entirely based on instructions of the programcodes and realize the functions of the embodiments through suchprocessing.

Furthermore, the program codes read from the storage medium can berecorded in a memory provided in a function extension card inserted intothe PC 600 or in a function extension unit connected to the computer.Then, based on the instructions of the program code, a CPU or the likeincluded in the function extension card or the function extension unitperforms an actual processing partially or entirely, and the functionsof the above preferred embodiments can be carried out by suchprocessing.

Further, as long as the program realizes the functions of the abovepreferred embodiments through the PC 600, it may be of an object codetype or a script data type supplied into the OS, or it may be a programexecuted by an interpreter.

The storage medium for storing the program therein may be, for example,a RAM, a NV-RAM, a floppy (registered trademark) disk, an optical disk,a magneto-optical disc, a CD-ROM, a CD-R, a CD-RW, a DVD (DVD-ROM,DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a nonvolatile memory card, aROM, and the like. Alternatively, the program may be downloaded from acomputer or a database (not shown) connected to the Internet, acommercial network, a local area network, or the like.

Hereinafter, a window member for particle monitoring in accordance witha fourth preferred embodiments of the present invention will bedescribed.

FIG. 8 provides a detailed cross sectional view to illustrate theconfiguration of the window member for particle monitoring.

The window member in accordance with the fourth embodiment is employedin lieu of the window member 219 for particle monitoring formed ofquartz in accordance with the first embodiment. Further, in the belowdescription, parts identical to those of the semiconductor manufacturingapparatus 1000 in accordance with the first embodiment will be assignedlike reference numerals, and explanation thereof will be omitted.

In FIG. 8, each of window members 219′ for particle monitoring has asubstantially columnar shape and is disposed between a rough pumpingline 200 and a particle monitoring unit 210. Specifically, the windowmembers 219′ are inserted into complementary openings provided in therough pumping line 200. Here, the window members 219′ are not limited tothe substantially columnar shapes to be inserted into the respectiveopenings of the rough pumping line 200, but may have, for example, ahollow cylindrical shape of a diameter approximately identical to thatof the rough pumping line 200, while forming a part of the rough pumpingline 200.

Moreover, each window member 219′ has a transparent base 219′a and asurface treatment layer 219′b obtained by performing a surface treatmenton the base 219′a. The base 219′a has a gas contact surface contacting agas within the rough pumping line 200 and a monitor surface connected tothe particle monitoring unit 210. The surface treatment layer 219′b isformed by performing a surface treatment to be described below on thegas contact surface of the base 219′a.

Though the base 219′a is preferably formed of glass containing siliconas its principal component, for example, quartz, it may be also formedof a transparent resin.

The surface treatment layer 219′b contains a material selected from agroup consisting of carbon (C), yttrium (Y), yttria (Y₂O₃), calciumfluoride (CaF₂), aluminum (Al) and alumina (Al₂O₃). In case the materialis carbon, crystalline diamond or diamond-like carbon is preferable. Byusing these materials, resistance to halogen-based plasma (hereinafter,referred to as “plasma resistance”) or resistance to active moleculescan be improved sufficiently.

Among the above group of materials, calcium fluoride has physicalcharacteristics as follows: insolubility in water, a melting point of1373° C., maximum usable temperature of 900° C., a hardness of a valueof 158.3 expressed by Knoop number, transmissive light wavelength rangeof 0.2 to 9.0 μm and a refractive index of 1.39 against the light with awavelength of 1000 cm⁻¹. Besides, calcium fluoride has highcorrosion-resistance against halogen, and also has a highpressure-resistance due to its great hardness. Furthermore, it is easyto attain calcium fluoride with high purity at a low price. Also,calcium fluoride is hard to dissolve in an aqueous solution of hydrogenfluoride, i.e., hydrofluoric acid than quartz is.

Among the above-specified materials, calcium fluoride is adequate toform the window members since it has high pressure-resistance. Moreover,since its maximum usable temperature is 900° C., it is adequate for usein the processing chamber 100 which is in a high-temperature atmosphereof about 900° C. Besides, due to its transmissive light wavelength rangelarger than that of quartz, it is adequate for optical measurement.Accordingly, it is most preferable to use calcium fluoride.

Further, individual aluminums and aluminum atoms among alumina reactwith fluorine among plasma, thus generating aluminum fluoride (AlF₃).Since so generated aluminum fluoride remains on the surface treatmentlayer 219′b, plasma resistance against fluorine becomes particularlyhigh.

Moreover, the halogen-based plasma contains halogen that corrodes quartzglass or a compound thereof. For example, the halogen-based plasma maybe a fluorine-based plasma including fluorine or a compound thereof,such as CF₄/Ar/O₂/CO plasma, F₂ plasma, carbon fluoride-based plasmasuch as CF₄, C₄F₈ and C₅F₈, and chlorine (Cl₂) plasma. Thesehalogen-based plasma contains active molecules such as halogen radicalsthat react with silicon atoms of glass or the like, resulting indeterioration of the glass or the like.

Furthermore, the content of the material forming the surface treatmentlayer 219′b is preferably set to range from 10 to 100 mass % of thetotal mass of the surface treatment layer 219′b. In case the content ofthe material is less than 10 mass %, the resistance of the surfacetreatment layer 219′b to the plasma or the active molecules cannot beimproved sufficiently.

Further, the thickness of the surface treatment layer 219′b preferablyranges from 100 nm to 100 μm. If the thickness is smaller than 100 nm,the surface treatment layer 219′b tends to be readily separated from thebase 219′a in case the surface treatment layer 219′b is formed of acoating film to be described later or tends to be readily corroded bythe fluorine-based plasma in case it is formed of a doping layer.Meanwhile, if the thickness of the surface treatment layer 219′b islarger than 100 μm, its formation on the base 219′a becomes difficult sothat the manufacturing cost thereof is increased, and further thetransparency of the surface treatment layer 219′b reduces, thus makingit difficult to monitor particles within the gas exhaust line by meansof the particle monitoring unit 210.

Hereinafter, the surface treatment of the gas contact surface of thebase 219′a will be described.

The surface treatment includes a coating processing for forming acoating film made of the same material as that of the surface treatmentlayer 219′b on the gas contact surface of the base 219′a and a dopingprocessing for forming a doping layer by way of doping the same materialas that of the surface treatment layer 219′b up to a preset depth fromthe gas contact surface. Meanwhile, besides the coating and the dopingprocessing, other methods may also be employed.

The coating processing includes, e.g., a method for melting a mixture ofthe above materials such as silicon dioxide, aluminum oxide and the likeand cooling it rapidly on the gas contact surface of the base 219′a, aspraying method for spraying the mixture in fusion onto the gas contactsurface of the base 219′a and a method for forming a film made of theabove materials by a sputtering or a PVD. By performing the coatingprocessing, it is possible to form the surface treatment layer 219′b onthe base 219′a easily.

The doping processing includes, e.g., an ion implantation method or amethod for partially melting the gas contact surface of the base 219′ato mix it with the above materials. Further, it is preferred to performa baking after doping the above materials. Also, though the interfacebetween the surface treatment layer 219′b and the base layer 219′a isnot definitely distinguishable in case the surface treatment layer 219′bis formed on the base 219′a by doping, the content of the dopedmaterials preferably needs to be in the above-specified content range atleast at a preset depth from the gas contact surface of the surfacetreatment layer 219′b. Since the surface treatment layer 219′b is hardlydetached from the base 219′a when it is formed by doping, the surfacetreatment layer 219′b is positively formed on the base 219′a.

With the window member 219′ for particle monitoring in FIG. 8, since thesurface treatment layer 219′b is formed on the base 219′a, the surfacetreatment layer 219′b serving as a new gas contact surface efficientlyexhibits resistance to plasma or active molecules. Accordingly, thefrequency of replacing the window member 219′ can be reduced. Moreover,with the decrease of the frequency of replacement, it is possible tomake the time period for maintaining the vacuum pressure in the gasexhaust line 200 longer, whereby the productivity of the semiconductormanufacturing apparatus 1000 can be improved.

In addition, since the window members 219′ for particle monitoring haveresistance to plasma or active molecules such that their deteriorationis suppressed, the particle monitoring unit 210 can surely monitorparticles including detached deposits, enabling exact evaluation of thecleanness of the semiconductor manufacturing apparatus 1000.

Moreover, in the fourth embodiment of the present invention, the windowmember 219′ for particle monitoring in FIG. 8 preferably has hightransparency with respect to the laser beam of a wavelength in the rangeof visible ray, which is emitted from the laser beam source 212. Also,the window member 219′ preferably has enough hardness to be used to facethe vacuum space.

Further, a film of magnesium fluoride may also be formed on the monitorsurface of the base 219′a, to thereby prevent reflections of lightincident on the window members 219′ for particle monitoring.

Further, though the window member 219′ for particle monitoring in FIG. 8has been described to include the base 219′a and the surface treatmentlayer 219′b in the fourth preferred embodiment, it may be formed of asingle bulk member made of calcium fluoride.

Also, the above-descried window members 219′ for particle monitoring canbe used in another vacuum vessel, for example, the processing chamber100 in FIG. 1 or a housing such as the particle monitoring unit 210 or apiping in FIG. 6. Besides, it may be used in another unit other than theparticle monitoring unit. A specific example thereof will be describedwith reference to FIG. 9.

FIG. 9 presents a detailed partial cross sectional view to describe theconfiguration of the semiconductor manufacturing apparatus 1000 in FIG.1.

In FIG. 9, a semiconductor manufacturing apparatus 1000″ furtherincludes a laser introduction unit 700 in addition to the componentsshown in FIG. 1. The laser introduction unit 700 has an in situ particlemonitoring unit (ISPM) 400 for monitoring particles in a processingchamber 100 at a location; and a charge coupled device (CCD) camera 500for capturing the image of, for example, the particles scattering thelaser beam. The particle monitoring unit 400 and the CCD camera 500 areconnected to the PC 600, and a CVD tool controller 620 is connected tothe PC 600 via a signal processing unit 610.

The particle monitoring unit 400 has a laser beam source 410 forirradiating a YAG laser beam of a preset wavelength of, for example, 532nm at an output of 2.5 kW and a pulse of 10 kHz; an optical system 420for forming the laser beam in a desired shape; a mirror 430 forreflecting the laser beam incident thereon after passing through theoptical system 420 in a direction toward the processing chamber 100; anda window member 440 through which the laser is introduced, the windowmember 440 being provided at a chamber wall 110 of the processingchamber 100. The window member 440 has the same configuration as that ofthe window member 219 for particle monitoring shown in FIG. 8 and ismade of the same material as that of the window member 219. The laserbeam reflected by the mirror 430 is guided into the processing chamber400 through the window member 440 for laser introduction. The beamintroduced into the processing chamber 100 is incident on a beam damper116 via slits 114 and 115.

Further, the CCD camera 500 photographs laser beams scattered byparticles within the processing chamber 100 through a window member (notshown) for the CCD camera provided at the chamber wall 110 of theprocessing chamber 100, and then inputs thus obtained image into the PC600. Thus, the CCD camera 500 can function as a sensor for counting thenumber of the laser beams scattered by the particles within theprocessing chamber 100, while measuring the pulse number of the laserbeams. The window member for the CCD camera is formed of the samematerial as that of the window member 219′ for particle monitoring shownin FIG. 8 and has the same configuration. For example, its surfacetreatment layer is formed of calcium fluoride, so that the erosion ofits surface is suppressed and thus the frequency of the window member'sreplacement can be reduced. Further, reduction in the sensitivity of thesensor can be prevented. Furthermore, a photomultiplier tube can be usedinstead of the CCD camera 500 as long as it functions as a sensor.

Moreover, the semiconductor manufacturing apparatus 1000″ has a focusring 117 disposed on a wafer stage 111, wherein the focus ring 117 isformed of the same material as that of the window member 219′ forparticle monitoring shown in FIG. 8 and has the same configuration.Therefore, erosion of the focus ring 117 can be prevented, whileachieving insulation, and thus the frequency of its replacement can bereduced.

Referring to FIG. 9, since the components within the processing chamber100 including the window member 440 for laser introduction, the windowmember for CCD camera, the focus ring 117 and the like are formed of thesame material as that of the window member 219′ shown in FIG. 8 and havethe same configurations, erosion of their surfaces can be suppressed,enabling reduction of the frequency of their replacement. In addition,due to the prevention of erosion of their surfaces, wafer contaminationcan be suppressed in the processing chamber 100.

The vacuum apparatus, and the particle monitoring method and program inaccordance with the present invention is not limited to the processingchamber or the load lock chamber of the semiconductor manufacturingapparatus, but may be applied to any vessel that defines an evacuablespace, for example, a manufacturing apparatus for fabricating a liquidcrystal such as a flat panel display and other substrate processingapparatuses.

Moreover, the window members for particle monitoring in accordance withthe preferred embodiments of the present invention may be used as atransparent window member disposed between a housing that defines anevacuable space and a particle monitoring unit for monitoring particleswithin the housing.

While the invention has been shown and described with respect to thepreferred embodiments, it will be understood by those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

1. A window member for particle monitoring comprising a transparentmember including: a transparent base which is formed of a transparentresin or glass containing silicon as a primary component; and a surfacetreatment layer consisting of a single layer formed by performing aprocessing on a gas contact surface of the transparent base which facesa gas within a housing, wherein the surface treatment layer is exposedto the gas within the housing, the surface treatment layer contains onematerial selected from a group consisting of yttrium and calciumfluoride to enhance corrosion resistance, and the window member isinstalled between the housing and a particle monitoring unit formonitoring particles within the housing.
 2. The window member of claim1, wherein the content of the selected material ranges from 10 to 100mass % of the total mass of the surface treatment layer.
 3. The windowmember of claim 1, wherein the surface treatment layer contains aluminumor alumina.
 4. The window member of claim 3, wherein the content of thealuminum or the alumina ranges from at least 10 mass % of the total massof the surface treatment layer.
 5. The window member of claim 1, whereinthe processing is a coating processing.
 6. The window member of claim 1,wherein the processing is a doping processing.
 7. The window member ofclaim 1, wherein the thickness of the surface treatment layer rangesfrom 100 nm to 10 μm.
 8. The window member of claim 1, wherein thehousing is formed of a vessel or a tube.
 9. The window member of claim1, wherein a film of magnesium fluoride is formed on a monitor surfaceof the transparent base, wherein the monitor surface is formed of asurface of the transparent base which faces the particle monitoringunit.
 10. The window member of claim 1, wherein the transparent base ismade of quartz.
 11. The window member of claim 1, wherein the housing isa gas line and the particle monitoring unit is installed on the gasline.